About 20 years ago, while still involved in the vintage staff at Duxford and also earning most of my living contracting as an LAE at STN, I was contacted one evening by a local newspaper.
The reporter stated that he had heard that I knew a bloke - who also worked at STN, at least around the time if the incident - who had stripped a Catalina to bits at Duxford. Transpires this fellow had falsified his licence and had been certifying at STN for an MRO there. His disappeared. I remember headlines such as "xxx aircraft worldwide will have to be recalled for 'maintenance checks' after having had work incorrectly inspected" or similar.
Someone knew I worked at both Duxford and STN and assumed I knew him; I did not but I heard he was not bad in technical respects.
At least in the UK, prospective employers are encouraged to contact the Competent Authority that issued the licence prior to proceeding.